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'Vegetative' patient speaks to scientists using his brainwaves

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Re: 'Vegetative' patient speaks to scientists using his brainwaves

#31

Post by mckilljoy »

albertni wrote: post #29
mckilljoy wrote: post #24

Earlier quoted context omitted.

So she went linearly through the whole alphabet until he found the letter he wanted? Sounds like somebody should have used a binary search! Hey-oooo!

I wonder which would actually faster - binary search on the standard ordered alphabet or going linearly in order of letter frequency. Even better - some hybrid algorithm that goes through the most common letters then goes into binary search for the remaining letters (many of which appear at approximately equal frequency)

You could probably also have a tree of the ~32 most common words. At the very beginning you could have a branch to choose whether you want to pick the 'word' tree or the 'letter' tree.

Re: 'Vegetative' patient speaks to scientists using his brainwaves

#32

Post by ajuc »

albertni wrote: post #29
mckilljoy wrote: post #24

Earlier quoted context omitted.

So she went linearly through the whole alphabet until he found the letter he wanted? Sounds like somebody should have used a binary search! Hey-oooo!

I wonder which would actually faster - binary search on the standard ordered alphabet or going linearly in order of letter frequency. Even better - some hybrid algorithm that goes through the most common letters then goes into binary search for the remaining letters (many of which appear at approximately equal frequency)

Binary search in unbalanced tree with shorter branches to more frequently used letters will be probably best (this is really huffman coding, isn't it?

Re: 'Vegetative' patient speaks to scientists using his brainwaves

#33

Post by loaristys »

This is an interesting new development in what was a couple of years ago an already observed phenomenon by half of the same team:

http://www.sciencemag.org/cgi/content/abstract/313/5792/1402

However, I think their publishing the idea that these patients were "conscious" is morally questionable. The reasons for this are expressed far more elegantly that I could manage by Parashkev Nachev in the following response:

http://www.sciencemag.org/cgi/reprint/sci;315/5816/1221a.pdf

Re: 'Vegetative' patient speaks to scientists using his brainwaves

#34

Post by kentosi »

Sforlips wrote: post #23
mckilljoy wrote: post #17

This whole story is really very fascinating, although a few details seem a bit odd. For example, the patient didn't answer the last question because.. he fell asleep? I would imagine if I was trapped inside my body and suddenly given a mechanism to communicate, I would be too excited to fall asleep. Did they observe any signs of excitement that I would expect a person to feel in this situation? Increased heart rate o…

Actually, detecting brain activity in an MRI requires long aquisition times. Around 30 seconds per answer at least (which is the duration used in this study AFAIK). That means that a single "yes" (imagining you're playing tennis) or "no" (imagining you're walking in your house) requires 30 seconds of sustained attention. This patient is obviously severely brain damaged. If you've ever seen a person recovering from br…

The idea that the patient was exhausted came to my mind as well.

Imagine being locked-in for so many years, and then suddenly being asked to imagine things. It's not as easy as it sounds: Imagining something in such a strict order over such a long period of time is actually quite exhausting.

Re: 'Vegetative' patient speaks to scientists using his brainwaves

#35

Post by yread »

aarongough wrote: post #6

If that patient is actually aware of his surroundings, then he has been trapped in a body with almost no sensory input for almost 6 years. Personally, that sounds like the worst hell imaginable. I've told everyone close to me that if I am injured badly they are to ask for 'no extreme measures' for this exact reason...

Check out 'Johny got his gun' (the movie or novel) for such an experience

Re: 'Vegetative' patient speaks to scientists using his brainwaves

#36

Post by rms »

metamemetics wrote: post #28
rms wrote: post #15

Earlier quoted context omitted.

I think within a few months you would descend into a self-hallucinatory dreamworld -- you'd be insane, but I don't think it would be the worst hell imaginable. Not even close.

Hallucinations are caused by sensory-deprivation rather than motor parylization. For example, float tanks, also there are specially designed rooms that have as close to no background noise as possible, and people report hearing all kind of audio hallucinations such as bees, etc. This test demonstrates he can at least hear sound. I'd imagine the effects would resemble senility from lack of engagement more. Also, inter…

I'm not sure that I meant hallucination in the clinical sense. I meant that if I was trapped inside my own mind for months on end, I would have nothing else to do besides create elaborate fantasy worlds in my mind and I suspect many others would do something similar.
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